This document discusses heat and temperature. It defines heat as a form of energy that flows spontaneously from hotter to cooler objects. It describes some key characteristics of heat, including that temperature is a measure of hotness and coldness, and heat causes physical changes like expansion and changes in state as well as chemical changes. It also discusses different scales for measuring temperature - Celsius, Fahrenheit, and Kelvin - and how to convert between them.

1. Heat
Part-1
FOR CLASS VII
By- Vivek Singh
ABPS JAGDISHPUR

2. Key points in this power point
• What is Heat?
• Characteristics of heat.
• Temperature
• Effect of heat
• Measurement of temperature

3. What is Heat?
• Heat is form of energy flowing
from one body of matter to
another spontaneously due to
their temperature difference.

4. • Heat always transfer from body of higher
temperature to body of lower temperature or
heat flows spontaneously from a hotter body to
a cooler body
Characteristics of heat

5. • In our daily life we come across a number of
objects. Some of them are hot and some of
them are cold.
E.g. - Tea is hot and ice is cold.
• Some objects are hotter than others and
some are colder than others.
• We often decide which object is hotter than
the other by touching the objects.
Hot and cold

6. • We cannot always rely on our
sense of touch to decide how hot
or how cold an object is.
• The hotness of an object is
measured by its temperature.
• When we add heat to body,
motion of its particle increase.
• When we remove heat from body,
motion of its particle decrease.

7. • Temperature is a measure of
the degree of hotness or
coldness of an object.
• The temperature of something
tells us how hot or cold
something is.
Temperature

8. • When body is heated various types of physical &
chemical change take place.
Physical changes
A) Change in temperature
• On adding heat to body, its temperature increase.
• On removal of heat from body, its temperature
decrease.
Effect of heat

9. b) Change of state
• On addition or removal of heat to/from body, there
is change in state of body.
• Ex- change of ice to water on addition of heat etc.
c) Thermal expansion
• The phenomenon of expansion of matter on heating
is called thermal expansion

10. Chemical changes
• On heating reactant , many case chemical changes
take place.

11. • Temperature is measured by a device called
thermometer.
• Temperature is measured in degrees.
Measurement of
temperature

12. Measurement of temperature
• There are three scale of measurement of
temperature.
• These are :-
1) Degree Celsius (°C)
2) Degree Fahrenheit (°F)
3) Kelvin (K)

13. • On the Celsius scale , the freezing point of water
is 0 °C whereas its boiling point is 100 °C. So this
scale is calibrate from 0 °C to 100 °C.
• On the Fahrenheit scale , the freezing point of
water is 32 °F whereas its boiling point is 212 °F.
So this scale is calibrate from 32 °F to 212 °F.

14. • Conversion of Celsius scale into Fahrenheit scale
• °F = °C x ( 9/5) + 32
• Conversion of Fahrenheit scale into Celsius scale
• °C =(°F - 32) x ( 5/9)
• Conversion of Celsius scale into Kelvin scale
• K = °C +273.15

15. Assignment
• Make note of all slides in your notebook.
• Write two examples of each (other than given in
slide)
• - Physical change
• - chemical change

16. THANK YOU